How we change what others think, feel, believe and do
Bring them news that supports your cause in some way.
Filter or edit actual news so they get a biased view of what is really happening.
Give them news that is completely false. Print fake newspapers or creates fake radio news reports so they believe a falsehood that leads them to give you what you want.
Let them write letters. Allow them to sneak them out, perhaps via the friendly guard or a visitor. Intercept them of course and fake the reply.
Let them see events, for example leading them past a room where a co-conspirator is being interrogated, is signing something, being treated well, etc.
Let them meet with outsiders, but only if the outsider is collaborating and carefully prepared.
"News flash: The whole of the ABC gang have been killed in a shoot-out with police."
You are allowed compassionate contact. Here's a letter from your wife.
I just thought you'd like to know that we're releasing all your other friends.
When people have been starved of contact with the outside world, they will jump on the news they actually get and are more likely to believe it.
When people only get partial news, they will fill in the rest of the detail -- often pessimistically.